New Study Is Easing Fears On AIDS and Mental Illness

By LAWRENCE K. ALTMAN, Special to The New York Times

Published: June 3, 1989

QUEBEC, June 2—
Fears that large numbers of people infected with the AIDS virus might suffer mental deterioration long before they develop the disease have been eased by new studies, researchers said here today.

A consensus has developed among experts that neurological and psychological complications from the virus rarely occur in the years before AIDS cripples the immune system, producing weight loss, fever and other symptoms, the researchers said at the first international meeting on the virus's effects on the brain. Fears about such complications were set off by earlier estimates that they affected up to 70 percent of people infected with the virus. That led the military to bar such people from certain jobs.

The earlier reports, including some in medical journals, also created deep concern about the risks of errors by infected people who hold jobs involving public safety, including commercial pilots and bus drivers. Low Risk of Complications

The picture emerging from the new studies about the neurological and psychological complications of infection with the AIDS, or human immunodeficiency, virus is far from complete. But experts have reached a consensus on the low risk of complications in the years before symptoms of the disease develop. During this interval the infected person appears healthy.

''Dementia is distinctly unusual in asymptomatic HIV-infected people,'' Dr. Justin McArthur, a neurologist at Johns Hopkins Hospital in Baltimore, told the meeting, of which he was a co-chairman. ''It affects less than 1 percent of HIV carriers.''

In the late stages of AIDS, however, neurological cations are common, participants said at the meeting, which was sponsored by the World Health Organization in Geneva, a United Nations agency, and the National Institutes of Health in Bethesda, Md.

World Health Organization officials have spoken out strongly against screening workers for HIV infection. After experts met in Geneva last year to evaluate preliminary versions of the information now being reported at public meetings, W.H.O. said tests to detect mental impairment among HIV-infected people were not justified. Data Called 'Pretty Firm'

In a telephone interview, Dr. Anthony S. Fauci, who heads the National Institute of Allergy and Infectious Diseases, called the newest data ''pretty firm and very important.''

Dr. Fauci recalled that three years ago some experts who cited the alarmingly high estimates of AIDS dementia contended that ''if scientists ever succeeded in suppressing the secondary infections that kill most patients, all you would be left with are demented people,'' But he added that ''those predictions are as wet as we said they would turn out to be.''

Crucial data have come from the Multicenter AIDS Cohort Study in which researchers financed by the National Institutes of Health are keeping track of nearly 5,000 gay and bisexual men in Baltimore, Chicago, Los Angeles and Pittsburgh.

The researchers tested 247 HIV-infected men who had not shown any signs of illness and, for purposes of scientific comparisons, 170 other men who were not infected with the AIDS virus. Members of the study group took several psychological tests every six months for 30 months. Cognitive Skills Compared

Dr. McArthur said the research team, of which he was a member, could detect no statistically significant difference in cognitive skills between the two groups.

Researchers from the Centers for Disease Control in Atlanta conducted a separate study among homosexual men in San Francisco with that city's Health Department.

Dr. Robert S. Janssen of the disease-control centers said the researchers administered up to 20 psychological tests to members of the groups. The researchers found no increase in neurological and psychological abnormalities in a group of apparently healthy HIV-infected homosexuals compared with those who were not HIV infected, Dr. Janssen said.

However, of 26 people who had developed symptoms from a form of HIV infection known as AIDS-related complex, 11, or 42 percent, had cognitive, psychological or neurological symptoms. This figure compared to 30, or 19 percent, of 157 men who were not HIV infected. Air Force Study Cited

In an Air Force study of people with AIDS, Dr. Douglas Marshall reported that tests showed that of 76 people in the study, only seven, or about 9 percent, had evidence of mental impairment. Dr. Marshall, who is chief neurologist at Wilford Hall Medical Center at Lackland Air Force Base in Texas, said the figure ''calmed my fears'' because he had been ''highly concerned'' about the 40 to 70 percent figures cited in some earlier studies.

Because the military screens all active duty personnel, Dr. Marshall said, the 9 percent figure from the Air Force probably more accurately reflects the overall incidence of mental complications in AIDS patients.

Participants at the meeting cited several reasons for the differences in the figures between the newer and earlier studies. A key one, they said, was that some of the highest figures came from medical centers to which AIDS dementia patients had been referred for care.

Another reason is that doctors have learned to more accurately diagnose AIDS dementia by excluding other conditions that can mimic it.

Dr. Anthony S. Fauci, an AIDS expert who heads the National Institute of Allergy and Infectious Diseases. He called the new data ''pretty firm and very important.''